Save Our Citrus! California's $2 billion citrus industry is at risk. A devastating plant disease called Huanglongbing, also known as HLB or citrus greening, has been found in Southern California. HLB kills citrus trees and there is no cure. The disease is spread by the Asian citrus psyllid, which has been found throughout southern and central California. We are calling on all facets of the citrus industry to join a collaborative effort to help save our state’s citrus.
California Citrus Pest & Disease Prevention Program A grower-funded program established to combat the Asian citrus psyllid and HLB. Key responsibilities of the program: – Detection & delimitation trapping – Visual survey – Residential treatment – Quarantine – Educational outreach
CPDPP Collaborates With Federal – USDA State – California Department of Food & Agriculture – Dept. of Pesticide Regulation – Office of Health Hazard Assessment – University of California - Cooperative Extension Local – County Agricultural Commissioners Industry – California Citrus Research Board – Growers Residents
What is the Asian Citrus Psyllid? Psyllids are small insects — about the size of an aphid. Young psyllids are yellow-orange and produce a white waxy substance. The Asian citrus psyllid feeds on the leaves and stems of citrus plants and can transmit HLB.
What is HLB? A plant disease for which there is no cure. ―Diseased trees eventually die. The disease causes blotchy yellow leaves and small, asymmetrical fruit with bitter juice. The best way to protect against the disease is to find and stop the pest from spreading.
The Impact of HLB In Florida, the insect and disease have caused the loss of more than 8,000 jobs, and the industry and workers it supports are struggling. In California, our commercial citrus industry and the more than 20,000 jobs it supports is at risk.
HLB & ACP Spread in North America Asian citrus psyllid, but not the disease Both the psyllid and HLB disease ACP and HLB came to California through the artificial movement of plant material. HLB has spread throughout Florida and is moving through Mexico. It has also infected trees in Texas. HLB has been found once in a residential tree in Southern California.
Asian Citrus Psyllid Spread in California ACP detected in Tijuana in June 2008 CDFA increased trapping/ visual surveys 2008- San Diego and Imperial 2009- Los Angeles, Orange and Ventura 2010- Riverside and San Bernardino 2012- Santa Barbara and Tulare 2013- Kern and Fresno 2014- San Luis Obispo
How is the Disease Controlled? Eradicating or suppressing ACP populations reduces the chance of the insect picking up and spreading the disease. Planting disease-free citrus trees. Infected trees will need to be destroyed to reduce the reservoir of disease.
Asian Citrus Psyllid Suppression Goal: Suppress the psyllid to buy time for researchers to develop solutions to the disease problem. – Slow the spread of the psyllid to new areas. – Prevent the psyllid from finding HLB-infected trees. – If it does find an infected tree, slow spread of HLB by reducing the vector population.
Asian Citrus Psyllid Control is Important – Even if HLB Becomes Widespread Infected psyllids create local bacterial infection points when they feed on a tree. The more infection points a tree has: ―The faster the infection takes over and destroys the tree; and – The easier it is for the psyllid to spread the disease. This is why Florida growers continue to treat for psyllids even though nearly all orchards are infected.
Detection Methods Yellow Sticky Traps CDFA is placing 1 trap/0.5 mi of perimeter (every 40 acres). Traps only adults. Weakly effective because if a psyllid is given a choice between a card and leaf flush, it prefers the flush.
Detection Methods Visual Surveys Conducted during periods of flush. Detects all stages; eggs, nymphs and adults. Flush locations on each tree are searched. Varieties that flush frequently and young trees receive extra attention.
Detection Methods Sweep Net Sampling Conducted any time of the year. Useful for detecting or monitoring adults. A large sweep net is used to stuff a branch into it and tap the branch. More effective method than tap sampling onto a sheet. Tap Sampling Conducted any time of the year. Useful for detecting or monitoring adults. A moist white plastic sheet is used on a clipboard and PVC to tap 3 times on four locations of the tree.
The Citrus Industry’s Role Be aggressive in sampling for the Asian citrus psyllid: ―Don’t rely on yellow sticky cards alone ―Increase scouting ―Use tap or sweep, and visual surveys to check orchards Sample regularly: – Conventional orchards: sample monthly – Organic orchards: sample every two weeks
ACP Insecticides Organophosphate Carbamate Pyrethroids Neonicotinoid foliar Neonicotinoid systemic Mixtures Spinosyn Avermectin Benzylurea Meti insecticide Tetronic acid Ryanodine Oils Pyrethrins + oil Isaria fumorsoroseus Chromobacterium subtsugae The UCIPM recommends the following chemical groups be used: Visit UCANR.edu/sites/ACP for more information.
Eradication Versus Areawide Management Eradication Strategy Trapping and visual surveys find a low density population of psyllids that is isolated from established populations and protected from both natural and artificial movement of psyllids. The combination of two broad spectrum insecticides applied to an 800 meter area eliminates psyllids from the area. Management Strategy Continuous areawide management program starts when established populations of psyllids are found in an area. Minimum of three ACP treatments per year focusing on flush and overwintering populations to suppress the psyllid below detectible levels.
Why Areawide Treatment Works? Areawide treatment is designed to be implemented in areas where the psyllid can no longer be eradicated. The psyllids are tiny and it’s hard to know exactly where they are. Most pesticides residue break down after 4-6 weeks. ―If treatments occur in a patchwork fashion, the psyllids move in when the residues break down and reinvade. If treatments occur over a large area over a two to three week period of time, they have the biggest impact on psyllids (no where to run, no where to hide). In California, the areawide control concept has already successfully been done for glassy-winged sharpshooter (GWSS).
Treating for the Asian citrus psyllid is critical for maintaining a vibrant citrus industry. Visit UCANR.edu/sites/ACP for information on the treatment products, protocols and standards that have proven most effective for managing this pest.UCANR.edu/sites/ACP
Cooperate Work closely with your County Agricultural Commissioner, local grower liaison, task force and CDFA in the event of a new psyllid find. Report any suspected findings of the Asian citrus psyllid. Please call your local agricultural commissioners. Stay informed. – Visit www.CitrusInsider.org regularly and sign up for regional and statewide updates.www.CitrusInsider.org Coordinate treatments with neighbor growers to get effective area wide treatment.
Best Practices When Out in the Field Growers should employ best management practices for the Asian citrus psyllid and encourage all others who take part in their operation — farm managers, farm labor contractors, pesticide applicators, etc. — to do the same.
Best Practices When Out in the Field Be careful not to transfer citrus plant material from one work site to another. – This could spread psyllids. Inspect all equipment and remove all citrus leaves and stems before leaving a site. – This means brushing off – including underneath – all equipment such as sprayers, tractors, ladders, trailers, flatbeds and bins. Inspect personal items carefully and brush them off before leaving a site. Inspect trees often, especially when there is new flush.
Industry Challenge: Abandoned Groves Uncared for orchards are a threat, as these trees can serve as reservoirs for the psyllid and HLB. These orchards must be removed in order to protect neighboring homeowner and commercial trees. – Abandoned orchards can be those with lack of irrigation and pest control, and no harvest for an extended period of time. If you have an orchard that you do not care for or know of an abandoned grove in your area, contact your local grower liaison who can work with you on solutions to remove these hazards and protect neighboring citrus trees.
The Natural Enemy There is a tiny parasitic wasp that lays its egg inside the psyllid nymph. The wasp develops and kills the nymph. Tamarixia radiata The wasps are specific to the Asian citrus psyllid and pose no risk to people or the environment.
Tamarixia Releases The hope is that the parasitoid will reduce the psyllid population in the urban areas and help to delay the spread of the disease. Natural enemies will not stop disease spread in commercial orchards because: Natural enemies do not control all of the psyllids. It only takes a few psyllids to spread the disease. Many of the treatments for other pests will reduce the effectiveness of the natural enemies.
Moving Forward Be aggressive – Sample regularly. – Control the Asian citrus psyllid to reduce the risk of HLB. Act quickly when a psyllid is found. Assist the program – Provide information about your orchards to help map the area. – Help identify areas that need help. Identify residents with 25 plus trees. Report unloved citrus.
Resources Citrus Insider (http://citrusinsider.org/)http://citrusinsider.org/ – Materials, maps and other links and information – Sign up for e-newsletter and stay informed University of California, Division of Agriculture and Natural Resources (http://ucanr.edu/sites/ACP )http://ucanr.edu/sites/ACP – For treatment products, protocols and standards
We are in this together! Enrico Ferro Ferroe@inbox.com 951-334-7611